Performance Evaluation of Bismuth Telluride (Bi2Te3) Based Thermoelectric Generator : A Simulation Study

Abstract

In this thesis, a detailed performance evaluation of a Bismuth telluride (Bi2Te3) based thermoelectric generator was conducted through simulation studies. Two computational methods were employed - non-equilibrium molecular dynamics (NEMD) and Boltzmann transport equation (BTE) to comprehensively determine the thermoelectric properties of Bi2Te3 over the temperature range of 100-800K. The NEMD method was used to calculate the lattice thermal conductivity, which was found to decrease with increasing temperature due to enhanced phonon scattering. The BTE method was then utilized to evaluate the elec tronic transport properties, including electronic thermal conductivity, electrical conductivity, and Seebeck coefficient. The results showed that electronic thermal conductivity increased with temperature as more charge carriers became thermally excited, while electrical con ductivity decreased due to the dominant effect of phonon scattering at higher temperatures. The Seebeck coefficient was observed to rise with increasing temperature as the energy dis tribution of electrons broadened, allowing more charge carriers to participate in the thermo electric process. By combining these calculated thermoelectric properties, the dimensionless figure of merit (ZT) was determined, and the efficiency of the Bi2Te3-based thermoelectric generator was estimated to be approximately 7.56% when the sink temperature was main tained at 300K and the source temperature was varied from 300-800K, in good agreement with literature report results.